Cadillac CT4 AC Compressor Failure: Warning Signs & Fix

Based on my experience with my 2018 CT5 that had similar automotive cooling issues, I can share some insights as someone with moderate experience in car maintenance. The symptoms you describe match what I encountered. Initially thought it was a refrigerant leak, but it turned out the AC control unit had failed completely. The AC compressor wasnt engaging because it wasnt receiving proper signals from the control module. The repair process at my trusted workshop involved: Complete diagnostic scan, Testing the AC compressor functionality, Checking the control unit circuits, Replacing the faulty control module, System reprogramming, Full AC system test Total cost was 980€ and took about 2 days to complete. The shop needed to order the control unit which caused most of the delay. To provide more specific guidance, could you share: Have you noticed any unusual noises before the system failed? Does the blower motor still work? Are there any other electrical issues in the car? What climate zone settings were you using when it failed? This information would help determine if your issue matches what I experienced or if its potentially something different in the auto refrigerant system.

Thanks for the feedback regarding the AC compressor failure. After my last service at 42705KM, I noticed the car air conditioning started acting up intermittently before failing completely. No strange noises before the failure, and the blower motor works fine. The climate control panel still lights up and responds, but theres no cold air. The air conditioning repair estimate from my shop seems significantly higher than your experience at 1450€. They insist a full AC system inspection is needed before confirming if its just the compressor or something more extensive in the cooling system. Would it be worth getting a second opinion given the price difference? The car has been well maintained with regular servicing, so Im surprised by such an early failure in the automotive cooling components.

Thanks for those additional details about your cooling system issues. Having gone through this with my CT5, I completely understand your concern about the price difference. The fact that your AC unit issues started after a service is interesting, this mirrors what happened with mine. However, your quote of 1450€ does seem steep compared to typical repair costs for these models. A few points to consider based on my experience: The blower working but no cold air typically points to either: A control module issue (which was my case), Low refrigerant from a slow leak, AC compressor electrical problems Since your car air conditioning worked intermittently before failing, this actually suggests it might be an electrical issue rather than a complete compressor failure. My intermittent problems were due to a failing control module, which was cheaper to fix than a full compressor replacement. Would definitely recommend getting a second opinion. When I got my first quote, it was around 1300€ because they assumed a full compressor replacement was needed. The second shop diagnosed it correctly, saving me about 320€. Make sure any shop does a proper pressure test and electrical diagnosis before replacing major components in the automotive cooling system.

Appreciate your thorough comparison of repair experiences and suggestions. After getting another quote today, youre absolutely right about the potential electrical nature of the vehicle HVAC problem. The second shop quoted 890€ for diagnostics and likely control module replacement, which aligns more with your repair costs. They explained that these cooling system issues often get misdiagnosed as complete compressor failures when its actually the control electronics causing the problem. Their initial testing showed the AC compressor itself might be fine, but its not receiving proper signals. Going to schedule the repair with the second shop next week. Their more systematic approach to diagnosing AC unit issues, starting with electrical testing before assuming major component failure, gives me more confidence. Thanks for helping me avoid potentially unnecessary repairs to the automotive cooling system. Its relieving to know others have successfully resolved similar problems without a complete compressor replacement. Will update once the repair is complete, as this could help others facing similar AC system failures in these models.